The cooling of internal components is critical to the operation of modern computer systems. The combined goals of increasing computing performance and smaller size drive computer designers to fill computer enclosures more densely with heat-generating components. If heat is not adequately removed from the computer enclosure, the temperature inside the enclosure may rise to levels that degrade the life and reliability of the computer.
Typically, a computer may use one or more fans to force air through the enclosure. The air movement increases the convective heat transfer coefficient between the electronic components and the air, and exhausts the heat efficiently to the surrounding environment.
Modern computers, especially when used as file servers, are often required to operate for extended periods. If a computer system fails or is shut down for maintenance, there may be disruptions in service, or complex measures may be required to avoid disruptions. For example, an additional, or redundant, computer may be required to provide service during the idle periods of the first computer, and a method must be provided for allowing the second computer to intercede when the first computer is idled. To avoid the complex measures and the cost of additional computers, it is desirable to build computer systems that require a minimum of down time. Ideally, some components may be repaired or replaced without shutting down the computer at all. Such components are often called “hot swappable” components.
The fan or fans in a computer system may be hot swappable, but in some systems, the attachment the fan to the computer system enclosure may utilize screws, wing nuts, bolts, thumb screws, or other hardware fasteners. The fasteners may add to the complexity and time required for servicing the computer system. They may also add to the complexity and cost of manufacturing the computer, both in the assembly process and in the process of maintaining parts inventories and supplier contacts. Often, the fasteners require that tools be used for replacing the fan or fans.
A computer system may employ fans on more than one side of the computer system enclosure. The fans may be configured so that one fan directs air into the enclosure and another fan on another side of the enclosure directs air out of the enclosure. In this way, both fans contribute to the motion of air through the enclosure. In some computer systems, a different fan design may be used in different locations on the enclosure. Using more than one fan design adds to the cost and complexity of the computer system and to the cost and complexity of maintaining the computer system.
In addition, the attachment for the fan or fans may be designed in such a way that it is possible to mount a fan incorrectly. This may result in a fan directing air in the wrong direction or even countering the effect of other fans, thus reducing the cooling effectiveness in the computer system.
If a computer system fan fails, the failure may not be immediately obvious, especially when a computer system uses multiple fans or when multiple computer systems are in close proximity. In the absence of an indication of the failure of a fan, the fan failure may go undetected, compromising the reliability of the computer system.
There is a need for a computer system fan arrangement that provides effective cooling with a minimum number of unique parts, that can be serviced quickly and effectively without tools and with little chance of error, and that can provide a signal when a fan fails.